In alt.solar.thermal Rod Speed wrote:
wrote

You cant just count the hits, you need to consider the source.

So, I continued, narrowing the chase.

http://www.google.com/search?q=Legionella+50oC
gives a shorter list, and has some interesting links.

Nope, none that are useful on that question which
substantiate their claims with rigorous science.

None that agree with you, I take it?

http://www.dhmh.state.md.us/html/legionella.htm
says you are just plain wrong using rigorous science.

I see adherence to the earlier advice.

You need new glasses then.

"Legionella die rapidly at 55oC (131o F)(3 log reduction within 1
hour), and are killed almost immediately at temperatures over 60oC
(140oF)."

Useless for your previous claim about 120F

In a continuum, or can you not hold a thought that long?
immediately at 60, 1 hour at 55, 2 hours at 50, not mentioned in this
quote, but wait, continue further if you can.

It was present in the tested systems because they were kept below 43c.

in a hospital hot water system, legionella is able to survive and
multiply, particularly as hot water temperatures are kept relatively
low to minimize the scald risk for patients [35]. In Maryland, state
regulations for nursing homes limit temperatures at the outlet to
110oF [43oC](COMAR 10.07.02); "

Again, so much for your 120F claim.

The tested samples had Legionella because they were kept below 110f. How
does that say anything about my 120f claim?

You live somewhere that has a code that requires hotter water.
I find attributions for lower temperatures, but no code requirement.

So, let me look in three places that I care about as references:
nih.gov and CDC.gov as research points, and ca.gov, because they regulate
my life.

Referring to cooling towers, not DWH:
http://www.energy.ca.gov/2005publica...0-2005-025.PDF
"Keep cold water below 25 C (77 F) and hot water above 55 C (131 F)."

From the Centers for Disease Control, whom I would consider to be the
foremost authority.
http://iier.isciii.es/mmwr/preview/m...l/rr5210a2.htm
"The bacteria are rarely found in municipal water supplies and tend to
colonize plumbing systems and point-of-use devices. To colonize,
legionellae usually require a temperature range of 77F--108F (25C--42.2C )
and are most commonly located in hot water systems. "

http://www.cdc.gov/ncidod/EID/vol12no04/05-1101.htm
"Legionella colonized 60% of the hot water systems before monochloramine
.... Increased prevalence of Legionella colonization was associated with
water heater temperatures 50C ...grows optimally at 35C and multiplies
between 25C and 42C"

Chloramine, not chlorine, is used in public water systems in California.

Further down on the CDC page is a recommendation for health care facilities
to use a system as you described, 61c water storage, and blending to no
more than 51 for delivery.

http://www.awt.org/Legionella03.pdf
seems to be an easy to read correlation of data from sources that I would
consider valuable. Page 12 speaks of DWH.

Pages that I've lost reference to refer to the desire for hotter
temperatures for Legionella protection, mitigated by the more pressing need
to prevent scalding.


I'm done now. You win.

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8,-122.5